Wednesday, November 30, 2016

‘And Fire in the Sky’ – In Space, to be more accurate!


Sounds both cool & rather ominous; No, it’s not a sky of rolling clouds of fire it is a controlled or at least expected fire. Expected because it is initiated by NASA and NASA is doing this with very good reason. Think of it, when you plan a vacation or trip you run scenarios and hope you plan every detail, even those ones that you hope you never have to use.


Well, NASA is no exception. In planning for a trip to Mars they need to take every possibility into account. Actually, NASA is known for its ability to be prepared – that fact has come in handy on many a mission and yet on just about every mission they learn about one area they could be even more prepared.


One area which is of concern is fire and fire aboard a spacecraft is usually considered catastrophic. Researchers actually know very little about how fire behaves in space and so they decided that now would be a far better time to check into it then to wait until something happen.


So NASA went about setting the biggest fire ever set in space. Where? The Cygnus resupply vessel. When planning a fire, what sort of materials do you use? That’s where NASA was careful to be smart. They wanted to fly the minimum amount of flammable stuff as almost everything taken into space is made from non-flammable materials BUT people up in space need some not so standard things, well, not for space, for piece of mind, comfort.  Basically, they need comfortable clothing; they need paper; they need towels, and all those things are flammable.

So far NASA has done this experiment two times and will be doing it one more time to complete the experiment. As the Cygnus resupply vessel returns to Earth, the fire is ignited remotely. It starts with consuming a large piece of cloth-cotton fiberglass cloth, inside a box as sensors measure the results. From there NASA researchers see how fast the fire grows – does it attain a steady growth rate or grow exponentially and what are the effects on the vehicle? A material choice in the SAFFIRE II was the same acrylic glass used in spacecraft windows.

The spacecraft that went up carrying the SAFFIRE II materials reached the ISS at the end of October. Orbital ATK's disposable cargo ship is expected to remain in there in orbit until Nov. 27th (it was released on November 21st) at which time controllers will initiate its fiery death as it meets the Earth's atmosphere. Its scheduled burn that will obliterate the spacecraft during re-entry will be preceded by the space fire experiment which is conducted inside its cabin.


Larger than the first SAFFIRE  experiment, the second SAFFIRE  II uses bigger samples that measure 2 inches by 12 inches long. The next (and last) of the SAFFIRE experiments will progress in size burning even larger materials and is anticipated in about 6 months from now.


After NASA had worked out the results from this round don’t think they have all the data they need to understand fires in space! Concepts for additional SAFFIRE missions are in development and would focus on the spread of flames, smoke propagation, detection and suppression.


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